Ferro-elastic domains with incommensurate twinning planes were observed in crystals by means of atomic force microscopy. It was found that each band on twinning boundaries had a fine surface structure which was composed of a shallow groove and a few striae. Many parallel stripes in the region between these 2 bands, which were revealed by high-resolution polarizing optical microscopy, were not detected.

S.Tsunekawa, K.Hara, R.Nishitani, A.Kasuya, T.Fukuda: Materials Transactions, 1995, 36[9], 1188-91